Prevalence of Arsenicosis in Terai, Nepal Makhan Maharjan 1 , Roshan R. Shrestha 1 , Sk. Akhtar Ahmad 2 , Chiho Watanabe 3 , and Ryutaro Ohtsuka 4 1 Environment and Public Health Organization, New Baneshwor, PO Box 4102, Kathmandu, Nepal, 2 Department of Occupational and Environmental Health, National Institute of Preventive and Social Medicine, Mohakhali, Dhaka 1212, Bangladesh, 3 Department of Human Ecology, School of International Health, Graduate School of Medicine, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan, and 4 National Institute for Environmental Studies, Tsukuba, Ibaraki ABSTRACT This paper summarizes the findings of surveys on arsenicosis cases conducted during 2001-2004 in terai, Nepal, by governmental and non-governmental organizations in their respective project areas and by some national and international institutes. Studies were conducted in six arsenic-contaminated districts of terai, namely Nawalparasi, Bara, Parsa, Rautahat, Rupandehi, and Kapilvastu. In these districts, arsenic contamination in tubewells varied from 2.1% to 25.7%. The prevalence of arsenicosis was, on average, 2.2% and varied from 0.7% in Kapilavastu district to 3.6% in Nawalparasi district. In the community-based study, the highest prevalence (18.6%) of arsenicosis was found in Patkhouli village of Nawalparasi, where 95.8% of tubewells were contaminated with arsenic. The prevalence of arsenicosis was higher in older age-groups (>50 years) of both the sexes. Males suffered more from arsenicosis than females (odds ratio: 2.50, 95% confidence interval 1.80-3.47). Skin manifestations, such as melanosis and keratosis, were the common symptoms of arsenicosis. Most patients were identified in the early or mild stage of the disease. They are expected to recover if further exposure to arsenic could be avoided by providing arsenic-safe drinking-water through intervention measures. Key words: Arsenic; Arsenic contamination; Skin lesions; Melanosis; Keratosis; Arsenicosis; Water supply; Prevalence; Nepal J HEALTH POPUL NUTR 2006 Jun;24(2):246-252 © 2006 International Centre for ISSN 1606-099 7$ 5.00+0.20 Diarrhoeal Disease Research, Bangladesh Correspondence and reprint requests should be addressed to: Dr. Makhan Maharjan Environment and Public Health Organization (ENPHO) New Baneshwor PO Box 4102, Kathmandu Nepal Email:maharjanmakhan@yahoo.com Fax: 00977-1-4491376 INTRODUCTION Nepal, a small land-locked South Asian country, lies between latitude 26º 22’ N to 30º 27’ N and longitude 80º 4’ E to 88º 12’ E. Elevation ranges from 60 to 8,848 metres, including the highest peak in the world—the Mount Everest. It is bounded on the north by Tibet (China), on the east by Sikkim and West Bengal, on the south by Bihar and Uttar Pradesh, and on the west by Uttar Pradesh of India (Fig.). It has roughly a rectangu- lar shape encompassing an area of 147,181 sq km with an average length of 885 km east to west and an aver- age breadth of 193 km north to south. Topographical diversity provides a wide range of climates, differing according to variations in altitude and location. Like- wise, annual rainfall differs with seasonal variations depending on the monsoon cycle. Nepal’s landscape is broadly defined by three contrasting physiographic bands, which run in more or less parallel, east to west: lowland terai region in the south; Hill region in the centre and Mountain region in the north (Fig.). The terai region, also called the ‘grainary’ of Nepal, is a low-lying tropical and sub-tropical belt of flat alluvial deposits stretching along the Nepal-India border that comprises 20 districts with an average width of 29 km. It is the northern extension of the Gangetic Plain and has an altitude ranging from 60 to 310 metre above the mean sea-level. Three major rivers—the Kosi, the Narayani (Gandak River), and the Karnali—feed the region. The terai makes up only 23% of the total land area but accommodates 50% of the total population of the country (1,2). Arsenic contamination in groundwater in Nepal is a new public-health issue. With the identification of